1. Field of the Invention
The invention relates to a method for producing a p-type doped material by doping a heterostructure semiconductor material, especially gallium arsenide/aluminum gallium arsenide (GaAs/AlGaAs), with silicon (Si) and annealing the doped semiconductor material under extreme gallium (Ga) rich conditions to obtain p-type materials having wide bandgaps.
2. Related Art
Impurity diffusion into group III-V compound semiconductors is an important step in the fabrication of opto-electronic devices. Recently the field has given much attention to the diffusion of silicon into gallium arsenide. The field has also recently given considerable attention to impurity induced disordering (IID) in GaAs/AlGaAs quantum well structures.
In particular, the diffusion of silicon into gallium arsenide has been investigated. For example, "The diffusion of Si in GaAs", G. R. Antell Solid State Electronics, Vol. 8, pp. 943-946 (1965), discloses the diffusion of silicon into gallium arsenide carried out at high temperatures in a sealed quartz capsule containing an overpressure of arsenic to prevent the diffusion of the arsenic out of the gallium arsenide substrate. The diffusivity and activation of silicon in gallium arsenide is proportional to the arsenic overpressure and the gallium vacancy concentrations. However, annealing the doped material in an arsenic overpressure environment produces a n-type doped material.
In "Diffusion of Si in Using Rapid Thermal Processing: Experiment and Model", M. E. Greiner et al. Applied Physics Letters, Vol. 44(8), pp. 750-752 (Apr. 15, 1984) discloses silicon diffusion from a thin, elemental-deposited silicon source, by using rapid thermal processing with several different encapsulants. The model discloses that paired silicon atoms move substitutionally by exchanging sites with either gallium or arsenic vacancies.
It is well known in the art that p-type layer disordered regions can be produced by diffusing zinc into layered heterostructures of III-V compounds such as GaAs/AlGaAs. However, silicon is a much preferred disordering impurity, because silicon produces a much more abrupt and reproducible transition from disordered to ordered material than zinc. However silicon, as presently used by the field in layer disordering, produces only n-type doped materials, e.g. see "Disorder of an Al.sub.x Ga.sub.1-x AsGaAs Superlattice by Donor Diffusion", K. Meehan, et al., Applied Physics Letters, Vol. 45(5), pp. 549-551 (Sep. 1, 1984). Therefore, there has been a long-felt need in the art for p-type layer disordering having transitional abruptness similar to that produced by n-type silicon diffusion.